Hydroxyurea has recently been sown to decrease the frequency of pain crisis in patients with sickle cell disease. In these same patients, HU as also led to a modest reduction in the rate of hemolysis. In vitro studies and a few pilot in vivo experiments suggest that clotrimazole, an imidazole antimycotic, can prevent the ion and water loss that is so characteristic of sickle red blood cell. The mechanism of action of CLT is different from that of HU.